Work began this week to return thousands of tonnes of illegally deposited waste from Co Fermanagh to the Republic.
Household rubbish was found buried under animal grazing land behind Philip Johnston's farmyard at Killadeas in the north of the county.
Addresses from Cork, Dublin and Wexford were on items discovered almost a decade ago.
Johnston was sentenced to four months' imprisonment after his 2007 conviction on two charges involving keeping controlled waste.
Northern Ireland Environment minister Mark Durkan said: "The continuation of work to remove and repatriate waste from these three sites this year further demonstrates our commitment to tackle illegal waste.
"This work will help protect the environment and I welcome our counterparts in the Republic of Ireland cooperating with us to address the scourge of illegal dumping."
Approximately 4,000 tonnes of waste have already been removed from a site close to Fivemiletown in South Tyrone and a further 4,000 tonnes from ground near Omagh.
An estimated 1,900 tonnes of household waste were found buried under farm land at Johnston's property after Environment and Heritage Service officers brought in a digger under warrant.
The Fermanagh operation is expected to take up to five weeks to complete.
It includes removing food packaging, plastics, papers and low-grade medical waste.
Johnston's defence had argued in court that waste paper was brought onto the farm to provide bedding for livestock quarantined due to a brucellosis outbreak, a Department of the Environment statement said.
Clearing 100 illegal waste-dumping sites in Northern Ireland could cost the taxpayer more than £250 million, a report has found.
It said waste crime was damaging the environment and economy in Northern Ireland.
Author Chris Mills, a former director of the Welsh Environment Agency, said the punishment did not fit the crime and the waste industry was extremely attractive and vulnerable to criminals who could make vast profits with relatively little risk.